The following expressions will be used herein, including in the claims, with the indicated definitions:
“frame buffer” denotes an area in a memory that holds a frame of data to be displayed on a display device (e.g., a CRT or flat panel display device). Typically, a frame buffer contains the data that determine a computer's “desktop.” In some embodiments of the invention, only a subset of the data in a frame buffer are displayed on the screen of a display device. For example, a subset of the data in a frame buffer can determine a “portal” (a part of a desktop) and the system is capable of displaying only the portal on the screen. For another example, the frame buffer contains more data than can be displayed on the screen of a display device, and the system is capable of downsampling or otherwise filtering the data in the frame buffer and displaying the filtered (e.g., downsampled) data on the screen or a portion of the screen. A graphics memory can include one or more frame buffers;
“graphics memory” denotes any memory that is coupled to a graphics processor. Typically, graphics memory stores display data (in a frame buffer or in each of at least two frame buffers), and also stores other data such as texture data, graphics shading programs, and/or display lists;
“window” denotes an area within a frame buffer. Typically, each window in a frame buffer corresponds to one application program running on a computer system (and holds data generated in accordance with such program); and
“simultaneous” display of data denotes display of the data such that a viewer perceives the data as being displayed simultaneously, even if the data are not all asserted to the display device simultaneously or if the display device does not simultaneously emit light indicative of all pixels determined by the data.